Does Aspiration With Culture Augmented With Percutaneous Core Biopsy Analysis Have Better Diagnostic Value Than Culture Alone for PJI in Large Joints? A Prospective Enhancement and Feasibility Study.

backgroundExisting diagnostic approaches in periprosthetic joint infections (PJIs) are primarily based on joint aspiration, with a reported sensitivity of 40% to 86%. "Dry taps," occurring in up to 40% of aspirations, reduce diagnostic accuracy. Core biopsies, which enable minimally invasive tissue sampling, are widely used across various medical specialties and represent a promising tool for application in orthopaedics. QUESTION/PURPOSE: Can the inclusion of core biopsy analysis, as opposed to a sole joint aspiration, enhance diagnostic accuracy for PJI in large joint (hip, knee, and shoulder) arthroplasties?

methodsIn this prospective enhancement study, 175 patients with painful large arthroplasties were recruited between September 2020 and September 2023. All patients underwent joint aspiration and core biopsy, leading to 181 primary data sets, of which 111 were excluded from final analysis for not reaching the endpoint or because of unrelated death, protocol breach, or a dry tap, which occurred in 34% (62 of 181) of examined joints. Diagnostic accuracy was assessed for sensitivity and specificity against the 2018 International Consensus Meeting (ICM) criteria, constituting the primary endpoint. Subsequent revision surgery, septic or aseptic, along with the microbiological evaluation of tissue samples and the sonicated prosthesis served as the confirmatory endpoint.

resultsCombined core biopsy and aspiration showed superior diagnostic performance compared with sole joint aspiration, with sensitivity and specificity of 93% (95% confidence interval [CI] 77% to 99%) and 97% (95% CI 87% to 99%), respectively, versus 79% (95% CI 60% to 92%) and 73% (95% CI 57% to 86%). The statistical difference, using the paired McNemar test for sensitivity and specificity, was p = 0.008 and p = 0.005, respectively. The area under the receiver operating characteristic curve was 0.77 (95% CI 0.65 to 0.88) for joint aspiration and 0.97 (95% CI 0.94 to 1.00) for combined aspiration plus core biopsy.

conclusionAddition of core biopsy enhances the accuracy of PJI diagnosis through higher sensitivity and specificity compared with sole joint aspiration, reducing the impact of dry taps and offering a more reliable PJI assessment. Incorporating it into the standard workflow could lead to earlier and more accurate diagnoses. LEVEL OF EVIDENCE: Level II, diagnostic study.